<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>1.简单动画-实现固定帧动画</title>
    <style>
        .bird {
            position: absolute;
            left: 100px;
            top: 100px;
            width:86px;
            height:60px;
            zoom: 0.5;
            background-repeat: no-repeat;
            background-image: url(https://p.ssl.qhimg.com/t01f265b6b6479fffc4.png);
            background-position: -178px -2px;
            animation: flappy .5s step-end infinite;
        }

        @keyframes flappy {
            0% {background-position: -178px -2px;}
            33% {background-position: -90px -2px;}
            66% {background-position: -2px -2px;}
        }
    </style>
</head>
<body>
    <div class="bird"></div>
</body>
</html>